The present invention provides an identification circuit, in particular one for an inkjet printhead using shift registers to transmit the inkjet printhead identification codes to a controller in order.
Consumer demand for product performance increases with technology advancement. Taking inkjet printers as an example, a variety of inkjet printers meeting various printing demands have been developed while each inkjet printer may correspond to a variety of cartridges, such as black ink cartridge, color ink cartridge, and cartridges capable of providing different numbers of jetting orifices on the printhead. The inkjet printer is capable of controlling individual cartridges through different control programs in light of the model or serial number assigned to each cartridge. Due to the various types of available cartridges, in order to prevent users from mistakenly installing an improper cartridge to an inkjet printer and rendering abnormal operation of the inkjet printer, when a cartridge is installed to an inkjet printer, the inkjet printer will identify the cartridge to ensure that the cartridge is applicable to such inkjet printer. An identification circuit is included in each printhead of the cartridge to allow the inkjet printer to identify the cartridge. The identification circuit of the cartridge is only used when the cartridge is first installed to the inkjet printer and is no longer needed once the cartridge has been identified.
FIGS. 1 and 2 illustrate a conventional inkjet printer 10 and a conventional cartridge 12, respectively. As shown in FIG. 1, the inkjet printer 10 includes at least one cartridge 12 installed to the inkjet printer 10. As shown in FIG. 2, the cartridge 12 includes a printhead 14 and a housing 16. The printhead 14 includes a chip 18 and a flexible print circuit board 13. The chip 18 is formed there on with a plurality of orifices 15. The housing 16 includes therein an ink reservoir 17 for storing ink. The printhead 14 and ink reservoir 17 communicate to one another. The ink in the ink reservoir 17 is sprayed from the orifices 15 through the printhead 14 upon heating so as to perform the prescribed printing operation.
FIGS. 3 and 4 disclose the identification circuit diagrams of a one-bit shift register 20 and a parallel in, serial out four-bit shift register 2, respectively, as disclosed in U.S. Pat. No. 5,940,095 entitled xe2x80x9cInk Jet Print Head Identification Circuit with Serial Out, Dynamic Shift Registersxe2x80x9d and assigned to Lexmark International Incorporation.
By referring to FIG. 3, in U.S. Pat. No. 5,940,095, a default logic binary code (0 or 1) is digitally encoded into the one-bit shift register 20 as being mask programmed during fabrication by:
(1) Connecting the source 24 of load transistor 22 to ground 21 and disconnecting the source 24 to voltage source 23, or
(2) Connecting the source 24 of load transistor 22 to a voltage source 23 and disconnecting the source 24 to ground 21.
Under condition (1), a default logic xe2x80x9c0xe2x80x9d encoded to the one-bit shift register 20 is read at the output line 28 when load 25, clock one 26, and clock two 27 are activated in sequence. On the other hand, under condition (2), a default lock xe2x80x9c1xe2x80x9d encoded to the one-bit shift register 20 is read at the output line 28.
FIG. 4 is the identification circuit diagram of a parallel in, serial out, four-bit shift register 2 as illustrated in U.S. Pat. No. 5,940,095. The circuit includes four serially connected one-bit shift registers 20a, 20b, 20c, 20d as shown in FIG. 3. The input lines of the one-bit shift registers 20b, 20c, 20d (the input line 29 in FIG. 3) are electrically connected to the output lines of the one-bit shift register 20a, 20b, 20c (the output line 28 in FIG. 3), respectively. When load 25, clock one 26, and clock two 27 are activated in order, the default binary codes encoded to the one-bit shift registers 20d, 20c, 20b, 20a are read from the output line 28 in sequence. If the identification code of a certain model number of an inkjet printhead is 0101, and the default binary codes being sequentially read from the one-bit shift registers 20d, 20c, 20b, 20a are 0, 1, 0 and 1, the printer (or computer) identifies the model number of the inkjet printhead. Similarly, if the identification code of a color inkjet printhead is 0001 and the default binary codes being sequentially read from the one-bit shift registers 20d, 20c, 20b, 20a are 0, 0, 0 and 1, the printer (or computer) identifies the inkjet printhead is for color printing.
In U.S. Pat. No. 5,940,095, however, the one-bit shift registers 20a, 20b, 20c, 20d are each mask programmed during fabrication to produce a default binary code (0 or 1) for allowing the printer (or computer) to identify the general information related to cartridges, while failing to record the current status of the inkjet printhead that being in use after leaving the factory.
Hence, the present invention provides an identification circuit for an inkjet printer cartridge capable of recording the current status of the inkjet printhead being in use after leaving the factory.
It is, thus, an object of the present invention to provide an ink jet printhead identification circuit and method constructed of fuses and other electronic components.
It is a further object of the present invention to provide an ink jet printhead identification circuit and method being encoded prior to leaving the factory for achieving its identification purpose (of identifying such general information of the cartridge as model number, serial number, color or gray-scale setting, and printing quality, etc.).
It is yet another object of the present invention to provide an ink jet printhead identification circuit and method that is encoded subsequent to leaving the factory for achieving its identification purpose (of detecting the current status of the cartridge).